/**
 * @license
 * Copyright 2015 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Class constructor for Tabs MDL component.
 * Implements MDL component design pattern defined at:
 * https://github.com/jasonmayes/mdl-component-design-pattern
 * @param {HTMLElement} element The element that will be upgraded.
 */
class MaterialTabs {

  constructor (element) {

    // Stores the HTML element.
    this.element_ = element;

    // Initialize instance.
    this.init();
  }

  /**
   * Store constants in one place so they can be updated easily.
   * @enum {string}
   * @private
   */
  get Constant_ () {
    // None at the moment.
  }

  /**
   * Store strings for class names defined by this component that are used in
   * JavaScript. This allows us to simply change it in one place should we
   * decide to modify at a later date.
   * @enum {string}
   * @private
   */
  get CssClasses_ () {
    return {
      TAB_CLASS: 'mdl-tabs__tab',
      PANEL_CLASS: 'mdl-tabs__panel',
      ACTIVE_CLASS: 'is-active',
      UPGRADED_CLASS: 'is-upgraded',

      MDL_JS_RIPPLE_EFFECT: 'mdl-js-ripple-effect',
      MDL_RIPPLE_CONTAINER: 'mdl-tabs__ripple-container',
      MDL_RIPPLE: 'mdl-ripple',
      MDL_JS_RIPPLE_EFFECT_IGNORE_EVENTS: 'mdl-js-ripple-effect--ignore-events'
    };
  }

  /**
   * Handle clicks to a tabs component
   * @private
   */
  initTabs_ (e) {

    if (this.element_.classList.contains(
        this.CssClasses_.MDL_JS_RIPPLE_EFFECT)) {
      this.element_.classList.add(
        this.CssClasses_.MDL_JS_RIPPLE_EFFECT_IGNORE_EVENTS);
    }

    // Select element tabs, document panels
    this.tabs_ = this.element_.querySelectorAll('.' +
        this.CssClasses_.TAB_CLASS);
    this.panels_ =
        this.element_.querySelectorAll('.' + this.CssClasses_.PANEL_CLASS);

    // Create new tabs for each tab element
    for (var i = 0; i < this.tabs_.length; i++) {
      new MaterialTab(this.tabs_[i], this);
    }

    this.element_.classList.add(this.CssClasses_.UPGRADED_CLASS);
  }

  /**
   * Reset tab state, dropping active classes
   * @private
   */
  resetTabState_ () {

    for (var k = 0; k < this.tabs_.length; k++) {
      this.tabs_[k].classList.remove(this.CssClasses_.ACTIVE_CLASS);
    }
  }

  /**
   * Reset panel state, droping active classes
   * @private
   */
  resetPanelState_ () {

    for (var j = 0; j < this.panels_.length; j++) {
      this.panels_[j].classList.remove(this.CssClasses_.ACTIVE_CLASS);
    }
  }

  init () {

    if (this.element_) {
      this.initTabs_();
    }
  }
}

class MaterialTab {

  constructor (tab, ctx) {

    if (!tab)
      return;

    if (ctx.element_.classList.contains(
        ctx.CssClasses_.MDL_JS_RIPPLE_EFFECT)) {

      var rippleContainer = document.createElement('span');
      rippleContainer.classList.add(ctx.CssClasses_.MDL_RIPPLE_CONTAINER);
      rippleContainer.classList.add(ctx.CssClasses_.MDL_JS_RIPPLE_EFFECT);
      var ripple = document.createElement('span');
      ripple.classList.add(ctx.CssClasses_.MDL_RIPPLE);
      rippleContainer.appendChild(ripple);
      tab.appendChild(rippleContainer);
    }

    tab.addEventListener('click', function(e) {
      e.preventDefault();
      var href = tab.href.split('#')[1];
      var panel = ctx.element_.querySelector('#' + href);
      ctx.resetTabState_();
      ctx.resetPanelState_();
      tab.classList.add(ctx.CssClasses_.ACTIVE_CLASS);
      panel.classList.add(ctx.CssClasses_.ACTIVE_CLASS);
    });

  }
}

var tabs = document.querySelectorAll('.mdl-js-tabs');
for (var t = 0; t < tabs.length; t++) {
  new MaterialTabs(tabs[t]);
}
